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<h2><a name="SECTION00201830000000000000000">
18.18.3 RequestHandler Objects</a>
</h2>

<p>
The request handler class must define a new <tt class="method">handle()</tt> method,
and can override any of the following methods.  A new instance is
created for each request.

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4309' xml:id='l2h-4309' class="function">finish</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Called after the <tt class="method">handle()</tt> method to perform any clean-up
actions required.  The default implementation does nothing.  If
<tt class="method">setup()</tt> or <tt class="method">handle()</tt> raise an exception, this
function will not be called.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4310' xml:id='l2h-4310' class="function">handle</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
This function must do all the work required to service a request.
The default implementation does nothing.
Several instance attributes are available to it; the request is
available as <tt class="member">self.request</tt>; the client address as
<tt class="member">self.client_address</tt>; and the server instance as
<tt class="member">self.server</tt>, in case it needs access to per-server
information.

<p>
The type of <tt class="member">self.request</tt> is different for datagram or stream
services.  For stream services, <tt class="member">self.request</tt> is a socket
object; for datagram services, <tt class="member">self.request</tt> is a string.
However, this can be hidden by using the  request handler subclasses
<tt class="class">StreamRequestHandler</tt> or <tt class="class">DatagramRequestHandler</tt>, which
override the <tt class="method">setup()</tt> and <tt class="method">finish()</tt> methods, and
provide <tt class="member">self.rfile</tt> and <tt class="member">self.wfile</tt> attributes.
<tt class="member">self.rfile</tt> and <tt class="member">self.wfile</tt> can be read or written,
respectively, to get the request data or return data to the client.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4311' xml:id='l2h-4311' class="function">setup</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Called before the <tt class="method">handle()</tt> method to perform any
initialization actions required.  The default implementation does
nothing.
</dl>

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